Beam sets for cell and beam mobility

ABSTRACT

Certain aspects of the present disclosure provide techniques for using beam sets for mobility management. A BS serving the UE may transmit, to the UE, information regarding one or more beam sets, wherein each of the beam sets comprise one or more reference beams used to transmit a reference signal. The BS may transmit, to the UE, one or more mobility parameters, wherein the mobility parameters are associated with the reference beams and one or more mobility event triggers. The BS may receive, from the UE, an indication of a detected mobility event, the mobility event is detected based, at least in part, on the mobility parameters. The BS may take one or more actions based, at least in part, on the indication. A UE may perform corresponding steps as described herein.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims benefit of priority from commonly-owned U.S.Provisional Application Ser. No. 62/417,247, filed Nov. 3, 2016, andentitled “Beam Sets for Cell and Beam Mobility,” which is expresslyincorporated herein by reference in its entirety.

INTRODUCTION

Aspects of the present disclosure relate to wireless communications, andmore particularly, using beam sets for mobility management of a userequipment (UE).

Wireless communication systems are widely deployed to provide varioustelecommunication services such as telephony, video, data, messaging,and broadcasts. Typical wireless communication systems may employmultiple-access technologies capable of supporting communication withmultiple users by sharing available system resources (e.g., bandwidth,transmit power). Examples of such multiple-access technologies includeLong Term Evolution (LTE) systems, code division multiple access (CDMA)systems, time division multiple access (TDMA) systems, frequencydivision multiple access (FDMA) systems, orthogonal frequency divisionmultiple access (OFDMA) systems, single-carrier frequency divisionmultiple access (SC-FDMA) systems, and time division synchronous codedivision multiple access (TD-SCDMA) systems.

In some examples, a wireless multiple-access communication system mayinclude a number of base stations, each simultaneously supportingcommunication for multiple communication devices, otherwise known asuser equipment (UEs). In LTE or LTE-A network, a set of one or more basestations may define an eNodeB (eNB). In other examples (e.g., in a nextgeneration or 5G network), a wireless multiple access communicationsystem may include a number of distributed units (DUs) (e.g., edge units(EUs), edge nodes (ENs), radio heads (RHs), smart radio heads (SRHs),transmission reception points (TRPs), etc.) in communication with anumber of central units (CUs) (e.g., central nodes (CNs), access nodecontrollers (ANCs), etc.), where a set of one or more distributed units,in communication with a central unit, may define an access node (e.g., anew radio base station (NR BS), a new radio node-B (NR NB), a networknode, 5G NB, gNB, etc.). A base station or DU may communicate with a setof UEs on downlink channels (e.g., for transmissions from a base stationor to a UE) and uplink channels (e.g., for transmissions from a UE to abase station or distributed unit).

These multiple access technologies have been adopted in varioustelecommunication standards to provide a common protocol that enablesdifferent wireless devices to communicate on a municipal, national,regional, and even global level. An example of an emergingtelecommunication standard is new radio (NR), for example, 5G radioaccess. It is designed to better support mobile broadband Internetaccess by improving spectral efficiency, lowering costs, improvingservices, making use of new spectrum, and better integrating with otheropen standards using OFDMA with a cyclic prefix (CP) on the downlink(DL) and on the uplink (UL) as well as support beamforming,multiple-input multiple-output (MIMO) antenna technology, and carrieraggregation.

However, as the demand for mobile broadband access continues toincrease, there exists a need for further improvements in NR technology.Preferably, these improvements should be applicable to othermulti-access technologies and the telecommunication standards thatemploy these technologies.

SUMMARY

The systems, methods, and devices of the disclosure each have severalaspects, no single one of which is solely responsible for its desirableattributes. Without limiting the scope of this disclosure as expressedby the claims which follow, some features will now be discussed briefly.After considering this discussion, and particularly after reading thesection entitled “Detailed Description” one will understand how thefeatures of this disclosure provide advantages that include improvedcommunications between access points and stations in a wireless network.

Certain aspects of the present disclosure relate to methods andapparatus for using beam sets for mobility management of a UE. Mobilitymanagement may refer to beam mobility (e.g., a UE switching from a firstactive beam to a second active beam) and/or cell mobility, (e.g., a UEswitching from a serving BS to a target BS).

Certain aspects of the present disclosure provide a method for wirelesscommunication that may be performed, for example, by a BS. The methodgenerally includes transmitting, to a user equipment (UE) served by theBS, information regarding one or more beam sets, wherein each of thebeam sets comprise one or more reference beams used to transmit areference signal, transmitting, to the UE, one or more mobilityparameters, wherein the mobility parameters are associated with thereference beams and one or more mobility event triggers, receiving, fromthe UE, an indication of a detected mobility event, the mobility eventdetected based, at least in part, on the mobility parameters, and takingone or more actions based, at least in part, on the indication.

Certain aspects of the present disclosure provide an apparatus forwireless communication that may be performed, for example, by a BS. Theapparatus generally includes means for transmitting, to a UE served bythe BS, information regarding one or more beam sets, wherein each of thebeam sets comprise one or more reference beams used to transmit areference signal, means for transmitting, to the UE, one or moremobility parameters, wherein the mobility parameters are associated withthe reference beams and one or more mobility event triggers, means forreceiving, from the UE, an indication of a detected mobility event, themobility event detected based, at least in part, on the mobilityparameters, and means for taking one or more actions based, at least inpart, on the indication.

Certain aspects of the present disclosure provide an apparatus forwireless communication that may be performed, for example, by a BS. Theapparatus generally includes at least one processor and a memory coupledto the at least one processor. The at least one processor is configuredto transmit, to a UE served by the BS, information regarding one or morebeam sets, wherein each of the beam sets comprise one or more referencebeams used to transmit a reference signal, transmit, to the UE, one ormore mobility parameters, wherein the mobility parameters are associatedwith the reference beams and one or more mobility event triggers,receive, from the UE, an indication of a detected mobility event, themobility event detected based, at least in part, on the mobilityparameters, and take one or more actions based, at least in part, on theindication.

Certain aspects of the present disclosure provide a computer readablemedium for wireless communication by BS having computer-executableinstructions stored thereon for transmitting, to a user equipment (UE)served by the BS, information regarding one or more beam sets, whereineach of the beam sets comprise one or more reference beams used totransmit a reference signal, transmitting, to the UE, one or moremobility parameters, wherein the mobility parameters are associated withthe reference beams and one or more mobility event triggers, receiving,from the UE, an indication of a detected mobility event, the mobilityevent detected based, at least in part, on the mobility parameters, andtaking one or more actions based, at least in part, on the indication.

Certain aspects of the present disclosure provide a method for wirelesscommunication that may be performed, for example, by a UE. The methodgenerally includes receiving, from a BS serving the UE, informationregarding one or more beam sets, wherein each of the beam sets compriseone or more reference beams used to transmit a reference signal,receiving, from the BS, one or more mobility parameters, wherein themobility parameters are associated with the reference beams and one ormore mobility event triggers, detecting a mobility event based, at leastin part, on the mobility parameters, and taking one or more actionsbased, at least in part, on the detected mobility event.

Certain aspects of the present disclosure provide an apparatus forwireless communication that may be performed, for example, by a UE. Theapparatus generally includes means for receiving, from a BS serving theUE, information regarding one or more beam sets, wherein each of thebeam sets comprise one or more reference beams used to transmit areference signal, means for receiving, from the BS, one or more mobilityparameters, wherein the mobility parameters are associated with thereference beams and one or more mobility event triggers, means fordetecting a mobility event based, at least in part, on the mobilityparameters, and means for taking one or more actions based, at least inpart, on the detected mobility event.

Certain aspects of the present disclosure provide an apparatus forwireless communication that may be performed, for example, by a UE. Theapparatus generally includes at least one processor and a memory coupledto the at least one processor. The at least one processor is configuredto receive, from a BS serving the UE, information regarding one or morebeam sets, wherein each of the beam sets comprise one or more referencebeams used to transmit a reference signal, receive, from the BS, one ormore mobility parameters, wherein the mobility parameters are associatedwith the reference beams and one or more mobility event triggers, detecta mobility event based, at least in part, on the mobility parameters,and take one or more actions based, at least in part, on the detectedmobility event.

Certain aspects of the present disclosure provide a computer readablemedium for wireless communication UE having computer-executableinstructions stored thereon for receiving, from a BS serving the UE,information regarding one or more beam sets, wherein each of the beamsets comprise one or more reference beams used to transmit a referencesignal, receiving, from the BS, one or more mobility parameters, whereinthe mobility parameters are associated with the reference beams and oneor more mobility event triggers, detecting a mobility event based, atleast in part, on the mobility parameters, and taking one or moreactions based, at least in part, on the detected mobility event.

To the accomplishment of the foregoing and related ends, the one or moreaspects comprise the features hereinafter fully described andparticularly pointed out in the claims. The following description andthe annexed drawings set forth in detail certain illustrative featuresof the one or more aspects. These features are indicative, however, ofbut a few of the various ways in which the principles of various aspectsmay be employed, and this description is intended to include all suchaspects and their equivalents.

BRIEF DESCRIPTION OF THE DRAWINGS

So that the manner in which the above-recited features of the presentdisclosure can be understood in detail, a more particular description,briefly summarized above, may be had by reference to aspects, some ofwhich are illustrated in the appended drawings. It is to be noted,however, that the appended drawings illustrate only certain typicalaspects of this disclosure and are therefore not to be consideredlimiting of its scope, for the description may admit to other equallyeffective aspects.

FIG. 1 is a block diagram conceptually illustrating an exampletelecommunications system, in accordance with certain aspects of thepresent disclosure.

FIG. 2 is a block diagram illustrating an example logical architectureof a distributed RAN, in accordance with certain aspects of the presentdisclosure.

FIG. 3 is a diagram illustrating an example physical architecture of adistributed RAN, in accordance with certain aspects of the presentdisclosure.

FIG. 4 is a block diagram conceptually illustrating a design of anexample BS and UE, in accordance with certain aspects of the presentdisclosure.

FIG. 5 is a diagram showing examples for implementing a communicationprotocol stack, in accordance with certain aspects of the presentdisclosure.

FIG. 6 illustrates an example of a DL-centric subframe, in accordancewith certain aspects of the present disclosure.

FIG. 7 illustrates an example of an UL-centric subframe, in accordancewith certain aspects of the present disclosure.

FIG. 8 illustrates an example of active beams, in accordance withcertain aspects of the present disclosure.

FIG. 9 example operations performed by a BS, in accordance with certainaspects of the present disclosure.

FIG. 10 illustrates example operations performed by a UE, in accordancewith certain aspects of the present disclosure.

To facilitate understanding, identical reference numerals have beenused, where possible, to designate identical elements that are common tothe figures. It is contemplated that elements disclosed in one aspectmay be beneficially utilized on other aspects without specificrecitation.

DETAILED DESCRIPTION

Aspects of the present disclosure provide apparatus, methods, processingsystems, and computer readable mediums for new radio (NR) (new radioaccess technology or 5G technology).

NR may support various wireless communication services, such as Enhancedmobile broadband (eMBB) targeting wide bandwidth (e.g. 80 MHz beyond),millimeter wave (mmW) targeting high carrier frequency (e.g. 60 GHz),massive MTC (mMTC) targeting non-backward compatible MTC techniques,and/or mission critical targeting ultra reliable low latencycommunications (URLLC). These services may include latency andreliability requirements. These services may also have differenttransmission time intervals (TTI) to meet respective quality of service(QoS) requirements. In addition, these services may co-exist in the samesubframe.

The following description provides examples, and is not limiting of thescope, applicability, or examples set forth in the claims. Changes maybe made in the function and arrangement of elements discussed withoutdeparting from the scope of the disclosure. Various examples may omit,substitute, or add various procedures or components as appropriate. Forinstance, the methods described may be performed in an order differentfrom that described, and various steps may be added, omitted, orcombined. Also, features described with respect to some examples may becombined in some other examples. For example, an apparatus may beimplemented or a method may be practiced using any number of the aspectsset forth herein. In addition, the scope of the disclosure is intendedto cover such an apparatus or method which is practiced using otherstructure, functionality, or structure and functionality in addition toor other than the various aspects of the disclosure set forth herein. Itshould be understood that any aspect of the disclosure disclosed hereinmay be embodied by one or more elements of a claim. The word “exemplary”is used herein to mean “serving as an example, instance, orillustration.” Any aspect described herein as “exemplary” is notnecessarily to be construed as preferred or advantageous over otheraspects.

The techniques described herein may be used for various wirelesscommunication networks such as LTE, CDMA, TDMA, FDMA, OFDMA, SC-FDMA andother networks. The terms “network” and “system” are often usedinterchangeably. A CDMA network may implement a radio technology such asUniversal Terrestrial Radio Access (UTRA), cdma2000, etc. UTRA includesWideband CDMA (WCDMA) and other variants of CDMA. cdma2000 coversIS-2000, IS-95 and IS-856 standards. A TDMA network may implement aradio technology such as Global System for Mobile Communications (GSM).An OFDMA network may implement a radio technology such as NR (e.g. 5GRA), Evolved UTRA (E-UTRA), Ultra Mobile Broadband (UMB), IEEE 802.11(Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, Flash-OFDMA, etc. UTRA andE-UTRA are part of Universal Mobile Telecommunication System (UMTS). NRis an emerging wireless communications technology under development inconjunction with the 5G Technology Forum (5GTF). 3GPP Long TermEvolution (LTE) and LTE-Advanced (LTE-A) are releases of UMTS that useE-UTRA. UTRA, E-UTRA, UMTS, LTE, LTE-A and GSM are described indocuments from an organization named “3rd Generation PartnershipProject” (3GPP). cdma2000 and UMB are described in documents from anorganization named “3rd Generation Partnership Project 2” (3GPP2). Thetechniques described herein may be used for the wireless networks andradio technologies mentioned above as well as other wireless networksand radio technologies. For clarity, while aspects may be describedherein using terminology commonly associated with 3G and/or 4G wirelesstechnologies, aspects of the present disclosure can be applied in othergeneration-based communication systems, such as 5G and later, includingNR technologies.

Example Wireless Communications System

FIG. 1 illustrates an example wireless network 100 in which aspects ofthe present disclosure may be performed. For example, the wirelessnetwork may be a new radio (NR) or 5G network. NR wireless communicationsystems may employ beams, where a BS and UE communicate via activebeams. As described herein, a BS may monitor active beams usingmeasurements of reference signals (e.g., MRS, CSI-RS, synch) transmittedvia reference beams.

As will be described in more detail herein, and as illustrated in FIG.8, active beams may include control beams and data beams. Sets of activebeams may have different functionalities, requirements, andcharacteristics. Given some of these differences, defining one set ofcell mobility parameters or beam mobility parameters for a wirelesssystem employing beams may be resource inefficient, provide inaccurateevent triggers, cause unnecessary mobility of a UE. Thus, aspects of thepresent disclosure provide beam sets and mobility parameters associatedwith each beam set. The mobility parameters may be used to detect anevent trigger for beam or cell mobility.

Because the functionalities and characteristics of beams may bedifferent, aspects of the present disclosure may advantageously makemobility decisions based on parameters specific to a beam set.Accordingly, the UE report more accurate event triggers because mobilityparameters may be specific to a beam set, consume less power by takingmeasurements associated with the mobility parameters for a beam set, andreduce signaling to a BS, by signaling event triggers associated withdefined mobility parameters for a beam set.

UEs 120 may be configured to perform the operations 1000 and methodsdescribed herein for detecting a mobility events based, at least inpart, on mobility parameters associated with a beam set. BS 110 maycomprise a transmission reception point (TRP), Node B (NB), 5G NB,access point (AP), new radio (NR) BS, etc.). BS 110 may be configured toperform the operations 900 and methods described herein for configuringbeam sets and mobility parameters associated with each of the beam sets.The BS may receive an indication of a detected mobility event based onthe mobility parameters and may make a decision regarding mobilitymanagement of the UE based on the event trigger.

As illustrated in FIG. 1, the wireless network 100 may include a numberof BSs 110 and other network entities. A BS may be a station thatcommunicates with UEs. Each BS 110 may provide communication coveragefor a particular geographic area. In 3GPP, the term “cell” can refer toa coverage area of a Node B and/or a Node B subsystem serving thiscoverage area, depending on the context in which the term is used. In NRsystems, the term “cell” and gNB, Node B, 5G NB, AP, NR BS, NR BS, orTRP may be interchangeable. In some examples, a cell may not necessarilybe stationary, and the geographic area of the cell may move according tothe location of a mobile base station. In some examples, the basestations may be interconnected to one another and/or to one or moreother base stations or network nodes (not shown) in the wireless network100 through various types of backhaul interfaces such as a directphysical connection, a virtual network, or the like using any suitabletransport network.

In general, any number of wireless networks may be deployed in a givengeographic area. Each wireless network may support a particular radioaccess technology (RAT) and may operate on one or more frequencies. ARAT may also be referred to as a radio technology, an air interface,etc. A frequency may also be referred to as a carrier, a frequencychannel, etc. Each frequency may support a single RAT in a givengeographic area in order to avoid interference between wireless networksof different RATs. In some cases, NR or 5G RAT networks may be deployed.

A BS may provide communication coverage for a macro cell, a pico cell, afemto cell, and/or other types of cell. A macro cell may cover arelatively large geographic area (e.g., several kilometers in radius)and may allow unrestricted access by UEs with service subscription. Apico cell may cover a relatively small geographic area and may allowunrestricted access by UEs with service subscription. A femto cell maycover a relatively small geographic area (e.g., a home) and may allowrestricted access by UEs having association with the femto cell (e.g.,UEs in a Closed Subscriber Group (CSG), UEs for users in the home,etc.). A BS for a macro cell may be referred to as a macro BS. A BS fora pico cell may be referred to as a pico BS. A BS for a femto cell maybe referred to as a femto BS or a home BS. In the example shown in FIG.1, the BSs 110 a, 110 b and 110 c may be macro BSs for the macro cells102 a, 102 b and 102 c, respectively. The BS 110 x may be a pico BS fora pico cell 102 x. The BSs 110 y and 110 z may be femto BS for the femtocells 102 y and 102 z, respectively. A BS may support one or multiple(e.g., three) cells.

The wireless network 100 may also include relay stations. A relaystation is a station that receives a transmission of data and/or otherinformation from an upstream station (e.g., a BS or a UE) and sends atransmission of the data and/or other information to a downstreamstation (e.g., a UE or a BS). A relay station may also be a UE thatrelays transmissions for other UEs. In the example shown in FIG. 1, arelay station 110 r may communicate with the BS 110 a and a UE 120 r inorder to facilitate communication between the BS 110 a and the UE 120 r.A relay station may also be referred to as a relay BS, a relay, etc.

The wireless network 100 may be a heterogeneous network that includesBSs of different types, e.g., macro BS, pico BS, femto BS, relays, etc.These different types of BSs may have different transmit power levels,different coverage areas, and different impact on interference in thewireless network 100. For example, macro BS may have a high transmitpower level (e.g., 20 Watts) whereas pico BS, femto BS, and relays mayhave a lower transmit power level (e.g., 1 Watt).

The wireless network 100 may support synchronous or asynchronousoperation. For synchronous operation, the BSs may have similar frametiming, and transmissions from different BSs may be approximatelyaligned in time. For asynchronous operation, the BSs may have differentframe timing, and transmissions from different BSs may not be aligned intime. The techniques described herein may be used for both synchronousand asynchronous operation.

A network controller 130 may couple to a set of BSs and providecoordination and control for these BSs. The network controller 130 maycommunicate with the BSs 110 via a backhaul. The BSs 110 may alsocommunicate with one another, e.g., directly or indirectly via wirelessor wireline backhaul.

The UEs 120 (e.g., 120 x, 120 y, etc.) may be dispersed throughout thewireless network 100, and each UE may be stationary or mobile. A UE mayalso be referred to as a mobile station, a terminal, an access terminal,a subscriber unit, a station, a Customer Premises Equipment (CPE), acellular phone, a smart phone, a personal digital assistant (PDA), awireless modem, a wireless communication device, a handheld device, alaptop computer, a cordless phone, a wireless local loop (WLL) station,a tablet, a camera, a gaming device, a netbook, a smartbook, anultrabook, a medical device or medical equipment, a biometricsensor/device, a wearable device such as a smart watch, smart clothing,smart glasses, a smart wrist band, smart jewelry (e.g., a smart ring, asmart bracelet, etc.), an entertainment device (e.g., a music device, avideo device, a satellite radio, etc.), a vehicular component or sensor,a smart meter/sensor, industrial manufacturing equipment, a globalpositioning system device, or any other suitable device that isconfigured to communicate via a wireless or wired medium. Some UEs maybe considered evolved or machine-type communication (MTC) devices orevolved MTC (eMTC) devices. MTC and eMTC UEs include, for example,robots, drones, remote devices, sensors, meters, monitors, locationtags, etc., that may communicate with a BS, another device (e.g., remotedevice), or some other entity. A wireless node may provide, for example,connectivity for or to a network (e.g., a wide area network such asInternet or a cellular network) via a wired or wireless communicationlink. Some UEs may be considered Internet-of-Things (IoT) devices.

In FIG. 1, a solid line with double arrows indicates desiredtransmissions between a UE and a serving BS, which is a BS designated toserve the UE on the downlink and/or uplink. A dashed line with doublearrows indicates interfering transmissions between a UE and a BS.

Certain wireless networks (e.g., LTE) utilize orthogonal frequencydivision multiplexing (OFDM) on the downlink and single-carrierfrequency division multiplexing (SC-FDM) on the uplink. OFDM and SC-FDMpartition the system bandwidth into multiple (K) orthogonal subcarriers,which are also commonly referred to as tones, bins, etc. Each subcarriermay be modulated with data. In general, modulation symbols are sent inthe frequency domain with OFDM and in the time domain with SC-FDM. Thespacing between adjacent subcarriers may be fixed, and the total numberof subcarriers (K) may be dependent on the system bandwidth. Forexample, the spacing of the subcarriers may be 15 kHz and the minimumresource allocation (called a ‘resource block’) may be 12 subcarriers(or 180 kHz). Consequently, the nominal FFT size may be equal to 128,256, 512, 1024 or 2048 for system bandwidth of 1.25, 2.5, 5, 10 or 20megahertz (MHz), respectively. The system bandwidth may also bepartitioned into subbands. For example, a subband may cover 1.08 MHz(i.e., 6 resource blocks), and there may be 1, 2, 4, 8 or 16 subbandsfor system bandwidth of 1.25, 2.5, 5, 10 or 20 MHz, respectively.

While aspects of the examples described herein may be associated withLTE technologies, aspects of the present disclosure may be applicablewith other wireless communications systems, such as NR.

NR may utilize OFDM with a CP on the uplink and downlink and includesupport for half-duplex operation using TDD. A single component carrierbandwidth of 100 MHz may be supported. NR resource blocks may span 12sub-carriers with a sub-carrier bandwidth of 75 kHz over a 0.1 msduration. Each radio frame may consist of 50 subframes with a length of10 ms. Consequently, each subframe may have a length of 0.2 ms. Eachsubframe may indicate a link direction (i.e., DL or UL) for datatransmission and the link direction for each subframe may be dynamicallyswitched. Each subframe may include DL/UL data as well as DL/UL controldata. UL and DL subframes for NR may be as described in more detailbelow with respect to FIGS. 6 and 7. Beamforming may be supported andbeam direction may be dynamically configured. MIMO transmissions withprecoding may also be supported. MIMO configurations in the DL maysupport up to 8 transmit antennas with multi-layer DL transmissions upto 8 streams and up to 2 streams per UE. Multi-layer transmissions withup to 2 streams per UE may be supported. Aggregation of multiple cellsmay be supported with up to 8 serving cells. Alternatively, NR maysupport a different air interface, other than an OFDM-based. NR networksmay include entities such CUs and/or DUs.

In some examples, access to the air interface may be scheduled, whereina scheduling entity (e.g., a base station) allocates resources forcommunication among some or all devices and equipment within its servicearea or cell. Within the present disclosure, as discussed further below,the scheduling entity may be responsible for scheduling, assigning,reconfiguring, and releasing resources for one or more subordinateentities. That is, for scheduled communication, subordinate entitiesutilize resources allocated by the scheduling entity. Base stations arenot the only entities that may function as a scheduling entity. That is,in some examples, a UE may function as a scheduling entity, schedulingresources for one or more subordinate entities (e.g., one or more otherUEs). In this example, the UE is functioning as a scheduling entity, andother UEs utilize resources scheduled by the UE for wirelesscommunication. A UE may function as a scheduling entity in apeer-to-peer (P2P) network, and/or in a mesh network. In a mesh networkexample, UEs may optionally communicate directly with one another inaddition to communicating with the scheduling entity.

Thus, in a wireless communication network with a scheduled access totime-frequency resources and having a cellular configuration, a P2Pconfiguration, and a mesh configuration, a scheduling entity and one ormore subordinate entities may communicate utilizing the scheduledresources.

As noted above, a RAN may include a CU and DUs. A NR BS (e.g., gNB, 5GNode B, Node B, transmission reception point (TRP), access point (AP))may correspond to one or multiple BSs. NR cells can be configured asaccess cell (ACells) or data only cells (DCells). For example, the RAN(e.g., a central unit or distributed unit) can configure the cells.DCells may be cells used for carrier aggregation or dual connectivity,but not used for initial access, cell selection/reselection, orhandover. In some cases DCells may not transmit synchronizationsignals—in some case cases DCells may transmit SS. NR BSs may transmitdownlink signals to UEs indicating the cell type. Based on the cell typeindication, the UE may communicate with the NR BS. For example, the UEmay determine NR BSs to consider for cell selection, access, handover,and/or measurement based on the indicated cell type.

FIG. 2 illustrates an example logical architecture of a distributedradio access network (RAN) 200, which may be implemented in the wirelesscommunication system illustrated in FIG. 1. A 5G access node 206 mayinclude an access node controller (ANC) 202. The ANC may be a centralunit (CU) of the distributed RAN 200. The backhaul interface to the nextgeneration core network (NG-CN) 204 may terminate at the ANC. Thebackhaul interface to neighboring next generation access nodes (NG-ANs)may terminate at the ANC. The ANC may include one or more TRPs 208(which may also be referred to as BSs, NR BSs, Node Bs, 5G NBs, APs, orsome other term). As described above, a TRP may be used interchangeablywith “cell.”

The TRPs 208 may be a DU. The TRPs may be connected to one ANC (ANC 202)or more than one ANC (not illustrated). For example, for RAN sharing,radio as a service (RaaS), and service specific AND deployments, the TRPmay be connected to more than one ANC. A TRP may include one or moreantenna ports. The TRPs may be configured to individually (e.g., dynamicselection) or jointly (e.g., joint transmission) serve traffic to a UE.

The local architecture 200 may be used to illustrate fronthauldefinition. The architecture may be defined that support fronthaulingsolutions across different deployment types. For example, thearchitecture may be based on transmit network capabilities (e.g.,bandwidth, latency, and/or jitter).

The architecture may share features and/or components with LTE.According to aspects, the next generation AN (NG-AN) 210 may supportdual connectivity with NR. The NG-AN may share a common fronthaul forLTE and NR.

The architecture may enable cooperation between and among TRPs 208. Forexample, cooperation may be present within a TRP and/or across TRPs viathe ANC 202. According to aspects, no inter-TRP interface may beneeded/present.

According to aspects, a dynamic configuration of split logical functionsmay be present within the architecture 200. As will be described in moredetail with reference to FIG. 5, the Radio Resource Control (RRC) layer,Packet Data Convergence Protocol (PDCP) layer, Radio Link Control (RLC)layer, Medium Access Control (MAC) layer, and a Physical (PHY) layersmay be adaptably placed at the DU or CU (e.g., TRP or ANC,respectively). According to certain aspects, a BS may include a centralunit (CU) (e.g., ANC 202) and/or one or more distributed units (e.g.,one or more TRPs 208).

FIG. 3 illustrates an example physical architecture of a distributed RAN300, according to aspects of the present disclosure. A centralized corenetwork unit (C-CU) 302 may host core network functions. The C-CU may becentrally deployed. C-CU functionality may be offloaded (e.g., toadvanced wireless services (AWS)), in an effort to handle peak capacity.

A centralized RAN unit (C-RU) 304 may host one or more ANC functions.Optionally, the C-RU may host core network functions locally. The C-RUmay have distributed deployment. The C-RU may be closer to the networkedge.

A DU 306 may host one or more TRPs (edge node (EN), an edge unit (EU), aradio head (RH), a smart radio head (SRH), or the like). The DU may belocated at edges of the network with radio frequency (RF) functionality.

FIG. 4 illustrates example components of the BS 110 and UE 120illustrated in FIG. 1, which may be used to implement aspects of thepresent disclosure. The BS may include a TRP. One or more components ofthe BS 110 and UE 120 may be used to practice aspects of the presentdisclosure. For example, antennas 452, mod/demod 454, processors 466,458, 464, and/or controller/processor 480 of the UE 120 and/or antennas434, mod/demod 432, processors 420, 430, 438, and/orcontroller/processor 440 of the BS 110 may be used to perform theoperations described herein and illustrated with reference to FIGS.9-10.

FIG. 4 shows a block diagram of a design of a BS 110 and a UE 120, whichmay be one of the BSs and one of the UEs in FIG. 1. For a restrictedassociation scenario, the base station 110 may be the macro BS 110 c inFIG. 1, and the UE 120 may be the UE 120 y. The base station 110 mayalso be a base station of some other type. The base station 110 may beequipped with antennas 434 a through 434 t, and the UE 120 may beequipped with antennas 452 a through 452 r.

At the base station 110, a transmit processor 420 may receive data froma data source 412 and control information from a controller/processor440. The control information may be for the Physical Broadcast Channel(PBCH), Physical Control Format Indicator Channel (PCFICH), PhysicalHybrid ARQ Indicator Channel (PHICH), Physical Downlink Control Channel(PDCCH), etc. The data may be for the Physical Downlink Shared Channel(PDSCH), etc. The processor 420 may process (e.g., encode and symbolmap) the data and control information to obtain data symbols and controlsymbols, respectively. The processor 420 may also generate referencesymbols, e.g., for the PSS, SSS, and cell-specific reference signal(CRS). A transmit (TX) multiple-input multiple-output (MIMO) processor430 may perform spatial processing (e.g., precoding) on the datasymbols, the control symbols, and/or the reference symbols, ifapplicable, and may provide output symbol streams to the modulators(MODs) 432 a through 432 t. Each modulator 432 may process a respectiveoutput symbol stream (e.g., for OFDM, etc.) to obtain an output samplestream. Each modulator 432 may further process (e.g., convert to analog,amplify, filter, and upconvert) the output sample stream to obtain adownlink signal. Downlink signals from modulators 432 a through 432 tmay be transmitted via the antennas 434 a through 434 t, respectively.

At the UE 120, the antennas 452 a through 452 r may receive the downlinksignals from the base station 110 and may provide received signals tothe demodulators (DEMODs) 454 a through 454 r, respectively. Eachdemodulator 454 may condition (e.g., filter, amplify, downconvert, anddigitize) a respective received signal to obtain input samples. Eachdemodulator 454 may further process the input samples (e.g., for OFDM,etc.) to obtain received symbols. A MIMO detector 456 may obtainreceived symbols from all the demodulators 454 a through 454 r, performMIMO detection on the received symbols if applicable, and providedetected symbols. A receive processor 458 may process (e.g., demodulate,deinterleave, and decode) the detected symbols, provide decoded data forthe UE 120 to a data sink 460, and provide decoded control informationto a controller/processor 480.

On the uplink, at the UE 120, a transmit processor 464 may receive andprocess data (e.g., for the Physical Uplink Shared Channel (PUSCH)) froma data source 462 and control information (e.g., for the Physical UplinkControl Channel (PUCCH) from the controller/processor 480. The transmitprocessor 464 may also generate reference symbols for a referencesignal. The symbols from the transmit processor 464 may be precoded by aTX MIMO processor 466 if applicable, further processed by thedemodulators 454 a through 454 r (e.g., for SC-FDM, etc.), andtransmitted to the base station 110. At the BS 110, the uplink signalsfrom the UE 120 may be received by the antennas 434, processed by themodulators 432, detected by a MIMO detector 436 if applicable, andfurther processed by a receive processor 438 to obtain decoded data andcontrol information sent by the UE 120. The receive processor 438 mayprovide the decoded data to a data sink 439 and the decoded controlinformation to the controller/processor 440.

The controllers/processors 440 and 480 may direct the operation at thebase station 110 and the UE 120, respectively. The processor 440 and/orother processors and modules at the base station 110 may perform ordirect, e.g., the execution of the functional blocks illustrated in FIG.9, and/or other processes for the techniques described herein. Theprocessor 480 and/or other processors and modules at the UE 120 may alsoperform or direct, e.g., the execution of thecorresponding/complementary processes for the techniques describedherein and as illustrated in FIG. 10. The memories 442 and 482 may storedata and program codes for the BS 110 and the UE 120, respectively. Ascheduler 444 may schedule UEs for data transmission on the downlinkand/or uplink.

FIG. 5 illustrates a diagram 500 showing examples for implementing acommunications protocol stack, according to aspects of the presentdisclosure. The illustrated communications protocol stacks may beimplemented by devices operating in a in a 5G system. Diagram 500illustrates a communications protocol stack including a Radio ResourceControl (RRC) layer 510, a Packet Data Convergence Protocol (PDCP) layer515, a Radio Link Control (RLC) layer 520, a Medium Access Control (MAC)layer 525, and a Physical (PHY) layer 530. In various examples thelayers of a protocol stack may be implemented as separate modules ofsoftware, portions of a processor or ASIC, portions of non-collocateddevices connected by a communications link, or various combinationsthereof. Collocated and non-collocated implementations may be used, forexample, in a protocol stack for a network access device (e.g., ANs,CUs, and/or DUs) or a UE.

A first option 505-a shows a split implementation of a protocol stack,in which implementation of the protocol stack is split between acentralized network access device (e.g., an ANC 202 in FIG. 2) anddistributed network access device (e.g., DU 208 in FIG. 2). In the firstoption 505-a, an RRC layer 510 and a PDCP layer 515 may be implementedby the central unit, and an RLC layer 520, a MAC layer 525, and a PHYlayer 530 may be implemented by the DU. In various examples the CU andthe DU may be collocated or non-collocated. The first option 505-a maybe useful in a macro cell, micro cell, or pico cell deployment.

A second option 505-b shows a unified implementation of a protocolstack, in which the protocol stack is implemented in a single networkaccess device (e.g., access node (AN), new radio base station (NR BS), anew radio Node-B (NR NB), a network node (NN), or the like.). In thesecond option, the RRC layer 510, the PDCP layer 515, the RLC layer 520,the MAC layer 525, and the PHY layer 530 may each be implemented by theAN. The second option 505-b may be useful in a femto cell deployment.

Regardless of whether a network access device implements part or all ofa protocol stack, a UE may implement an entire protocol stack (e.g., theRRC layer 510, the PDCP layer 515, the RLC layer 520, the MAC layer 525,and the PHY layer 530).

FIG. 6 is a diagram 600 showing an example of a DL-centric subframe. TheDL-centric subframe may include a control portion 602. The controlportion 602 may exist in the initial or beginning portion of theDL-centric subframe. The control portion 602 may include variousscheduling information and/or control information corresponding tovarious portions of the DL-centric subframe. In some configurations, thecontrol portion 602 may be a physical DL control channel (PDCCH), asindicated in FIG. 6. The DL-centric subframe may also include a DL dataportion 604. The DL data portion 604 may sometimes be referred to as thepayload of the DL-centric subframe. The DL data portion 604 may includethe communication resources utilized to communicate DL data from thescheduling entity (e.g., UE or BS) to the subordinate entity (e.g., UE).In some configurations, the DL data portion 604 may be a physical DLshared channel (PDSCH).

The DL-centric subframe may also include a common UL portion 606. Thecommon UL portion 606 may sometimes be referred to as an UL burst, acommon UL burst, and/or various other suitable terms. The common ULportion 606 may include feedback information corresponding to variousother portions of the DL-centric subframe. For example, the common ULportion 606 may include feedback information corresponding to thecontrol portion 602. Non-limiting examples of feedback information mayinclude an ACK signal, a NACK signal, a HARQ indicator, and/or variousother suitable types of information. The common UL portion 606 mayinclude additional or alternative information, such as informationpertaining to random access channel (RACH) procedures, schedulingrequests (SRs), and various other suitable types of information. Asillustrated in FIG. 6, the end of the DL data portion 604 may beseparated in time from the beginning of the common UL portion 606. Thistime separation may sometimes be referred to as a gap, a guard period, aguard interval, and/or various other suitable terms. This separationprovides time for the switch-over from DL communication (e.g., receptionoperation by the subordinate entity (e.g., UE)) to UL communication(e.g., transmission by the subordinate entity (e.g., UE)). One ofordinary skill in the art will understand that the foregoing is merelyone example of a DL-centric subframe and alternative structures havingsimilar features may exist without necessarily deviating from theaspects described herein.

FIG. 7 is a diagram 700 showing an example of an UL-centric subframe.The UL-centric subframe may include a control portion 702. The controlportion 702 may exist in the initial or beginning portion of theUL-centric subframe. The control portion 702 in FIG. 7 may be similar tothe control portion described above with reference to FIG. 6. TheUL-centric subframe may also include an UL data portion 704. The UL dataportion 704 may sometimes be referred to as the payload of theUL-centric subframe. The UL portion may refer to the communicationresources utilized to communicate UL data from the subordinate entity(e.g., UE) to the scheduling entity (e.g., UE or BS). In someconfigurations, the control portion 702 may be a physical DL controlchannel (PDCCH).

As illustrated in FIG. 7, the end of the control portion 702 may beseparated in time from the beginning of the UL data portion 704. Thistime separation may sometimes be referred to as a gap, guard period,guard interval, and/or various other suitable terms. This separationprovides time for the switch-over from DL communication (e.g., receptionoperation by the scheduling entity) to UL communication (e.g.,transmission by the scheduling entity). The UL-centric subframe may alsoinclude a common UL portion 706. The common UL portion 706 in FIG. 7 maybe similar to the common UL portion 606 described above with referenceto FIG. 6. The common UL portion 706 may include additional oralternative information pertaining to channel quality indicator (CQI),sounding reference signals (SRSs), and various other suitable types ofinformation. One of ordinary skill in the art will understand that theforegoing is merely one example of an UL-centric subframe andalternative structures having similar features may exist withoutnecessarily deviating from the aspects described herein.

In some circumstances, two or more subordinate entities (e.g., UEs) maycommunicate with each other using sidelink signals. Real-worldapplications of such sidelink communications may include public safety,proximity services, UE-to-network relaying, vehicle-to-vehicle (V2V)communications, Internet of Everything (IoE) communications, IoTcommunications, mission-critical mesh, and/or various other suitableapplications. Generally, a sidelink signal may refer to a signalcommunicated from one subordinate entity (e.g., UE1) to anothersubordinate entity (e.g., UE2) without relaying that communicationthrough the scheduling entity (e.g., UE or BS), even though thescheduling entity may be utilized for scheduling and/or controlpurposes. In some examples, the sidelink signals may be communicatedusing a licensed spectrum (unlike wireless local area networks, whichtypically use an unlicensed spectrum).

A UE may operate in various radio resource configurations, including aconfiguration associated with transmitting pilots using a dedicated setof resources (e.g., a radio resource control (RRC) dedicated state,etc.) or a configuration associated with transmitting pilots using acommon set of resources (e.g., an RRC common state, etc.). Whenoperating in the RRC dedicated state, the UE may select a dedicated setof resources for transmitting a pilot signal to a network. Whenoperating in the RRC common state, the UE may select a common set ofresources for transmitting a pilot signal to the network. In eithercase, a pilot signal transmitted by the UE may be received by one ormore network access devices, such as an AN, or a DU, or portionsthereof. Each receiving network access device may be configured toreceive and measure pilot signals transmitted on the common set ofresources, and also receive and measure pilot signals transmitted ondedicated sets of resources allocated to the UEs for which the networkaccess device is a member of a monitoring set of network access devicesfor the UE. One or more of the receiving network access devices, or a CUto which receiving network access device(s) transmit the measurements ofthe pilot signals, may use the measurements to identify serving cellsfor the UEs, or to initiate a change of serving cell for one or more ofthe UEs.

mmWave Systems

As used herein, the term mmWave generally refers to spectrum bands invery high frequencies such as 28 GHz. Such frequencies may provide verylarge bandwidths capable of delivering multi-Gbps data rates, as well asthe opportunity for extremely dense spatial reuse to increase capacity.Traditionally, these higher frequencies were not robust enough forindoor/outdoor mobile broadband applications due to high propagationloss and susceptibility to blockage (e.g., from buildings, humans, andthe like).

Despite these challenges, at the higher frequencies in which mmWaveoperates, the small wavelengths enable the use of a large number ofantenna elements in a relatively small form factor. This characteristicof mmWave can be leveraged to form narrow directional beams that cansend and receive more energy, which may help overcome thepropagation/path loss challenges.

These narrow directional beams can also be utilized for spatial reuse.This is one of the key enablers for utilizing mmWave for mobilebroadband services. In addition, the non-line-of-site (NLOS) paths(e.g., reflections from nearby building) can have very large energies,providing alternative paths when line-of-site (LOS) paths are blocked.Aspects of the present disclosure may take advantage of such directionalbeams, for example, by using sets of beams for beam and cell mobilitymanagement.

Example Beam Sets For Cell and Beam Mobility

Some legacy wireless communication standards base UE mobility decisionson cell-specific reference signals (CRS) transmitted by serving andtarget BSs. For example, a CRS may be transmitted in a radio frame, a UEmay measure the CRS, and the UE may report a reference signal receivepower (RSRP) associated with the measured CRS to the BS. Because everycell may transmit a CRS, the measured RSRP may be “linked” to a cell.Measurements of CRS from a serving cell and one or more non-servingcells may be used to make handover decisions.

In some wireless systems, however, a serving BS may not regularlytransmit a CRS. Instead, for example, a reference signal may betransmitted on-demand or as needed. Accordingly, mobility decisions in acommunication system employing beams may be based on one or morereference beams as described herein.

FIG. 8 illustrates an example of active beams 800, in accordance withaspects of the present disclosure. A BS and a UE may communicate using aset of active beams. Active beams may refer to BS and UE beam pairs thatare used to transmit data and control channels. A data beam may be usedto transmit data and a control beam may be used to transmit controlinformation. As illustrated in FIG. 8, data beam BS-A1 may be used totransmit DL data and control beam BS-A2 may be used to transmit DLcontrol information. A control beam, which may serve more than one UE,may be broader than a data beam. A control/data beam UE-A1 may be usedto transmit both control and data. As illustrated, both UL control anddata are transmitted using a same beam; however, the data and controlinformation may be transmitted using different beams. Similarly, dataand control may be transmitted by the BS using different beams (asillustrated) or a same beam.

In wireless communication systems employing beams, such as mmWavesystems, high path loss may present a challenge. Accordingly, techniquesincluding hybrid beamforming (analog and digital), which are not presentin 3G and 4G systems, may be used in such wireless systems. Hybridbeamforming creates narrow beam patterns to users (e.g., UEs), which mayenhance link budget/signal to noise ratio (SRN). As described above, aBS and UE may communicate over active beams. Active beams may bereferred to as serving beams. Active beams may include BS and UE beampairs that carry data and control channels such as PDSCH, PDCCH, PUSCH,and PUCCH.

A BS may monitor beams using beam measurements and based on feedbackfrom a UE. For example, a BS may monitor active beams using DL referencesignals. A BS may transmit a DL RS, such as a measurement referencesignal (MRS), channel state information reference signal (CSI-RS), asynchronization (synch) signal or a new radio reference signal (NR-synchsignal (SS)).

NR defines several types of synchronization signals—NR-PSS, NR-SSS, anddemodulated reference signal (DMRS) associated with PBCH. NR-PSS isdefined at least for initial symbol boundary synchronization to the NRcell. NR-SSS is defined for detection of NR cell ID or at least part ofNR cell ID. A UE may report, to the BS, a reference signal receive power(RSRP) associated with any received reference signal, such as thosedescribed above. In this manner, the BS may monitor active beams.Additionally or alternatively, the BS may monitor beams based on anytransmitted RS.

Sets of active beams may have different functionalities,characteristics, and requirements. Stated otherwise, the functionalitiesof one or more active beams may be different than the functionalitiesother active beams. For example, a first set of active beams may includecontrol beam and a second set of active beams may include datatransmissions. As another example, beams in a first set of active beamsmay be transmitted in a first direction and beams in a second set ofactive beams may be transmitted in a second direction, different thanthe first direction.

During multi-link communication, a UE may simultaneously be connected toa first BS in the first direction and to a second BS in the seconddirection. Beam shapes for each beam set of the active beams may vary.For example, as described above, the shape of control beams from a BSmay be different than a shape of data beams from the same base station.

Given the different functionalities and characteristics of beams, usingone set of parameters to determine an event trigger for beam or cellmobility may be undesirable as one set of mobility parameters may notcater to the functionalities of all active beams. Using one set ofparameters to determine a trigger event may trigger unnecessary mobilityevents (e.g., trigger an event which may not have been triggered had theUE been monitoring parameters specific to a beam set), waste power atthe UE (e.g., by performing unnecessary measurements), and create excesssignaling between the UE and BS (e.g., based on detected events whichmay not have been detected had the UE been monitoring parametersspecific to a beam set).

Thus, aspects of the present disclosure provide methods and apparatusfor using beam sets to assist in mobility management of a UE. Mobilitymanagement may refer to cell mobility and/or beam mobility. According toaspects, sets of beams may be configured. Each set of beams may beassociated with cell or beam mobility parameters. A BS may indicate, tothe UE, one or more sets of beam and mobility parameters associated witheach of the beam sets. The mobility parameters may be associated withone or more mobility event triggers. The UE may take measurements andobtain signal quality. The UE may detect a mobility event based on themeasurements/signal quality and the received parameters for beams in thebeam set. The UE may transmit an indication of the detected mobilityevent to the BS. In response, the BS may handover the UE to a target BSor switch from serving the UE to a second active beam (from a firstactive beam).

FIG. 9 illustrates example operations performed by a BS. The BS mayinclude one or more modules of the BS 110 illustrated in FIG. 4.

At 902, the BS may transmit, to a UE served by the BS, informationregarding one or more beam sets, wherein each of the beam sets compriseone or more reference beams used to transmit a reference signal. At 904,the BS may transmit, to the UE, one or more mobility parameters, whereinthe mobility parameters are associated with the reference beams and oneor more mobility event triggers. At 906, the BS may receive, from theUE, an indication of a detected mobility event, wherein the mobilityevent is detected by the UE based, at least in part, on the mobilityparameters. At 908, the BS, take one or more actions based, at least inpart, on the indication.

FIG. 10 illustrates example operations 1000 which may be performed byUE, according to aspects of the present disclosure. The UE may includeone or more modules of the UE 120 illustrated in FIG. 4.

At 1002, the UE may receive, from a BS serving the UE, informationregarding one or more beam sets, wherein each of the beam sets compriseone or more reference beams used to transmit a reference signal. At1004, the UE may receive, from the BS, one or more mobility parameters,wherein the mobility parameters are associated with the reference beamsand one or more mobility event triggers. At 1006, the UE may detect amobility event based, at least in part, on the mobility parameters. At1008, the UE may take one or more actions based, at least in part, onthe detected mobility event.

As described herein, a beam set may include BS beams only or BS-UE beampairs. According to aspects, the BS may signal one or more beam sets toone or more UEs. Each of the beam sets may include at least onereference beam, which is used to transmit, by the BS, at least onereference signal. Event triggers for a respective beam set may be based,at least in part, on signal quality measurements associated with thereference beam of the beam set. Accordingly, event triggers may be basedon reference beams belonging to the beam set and one or more mobilityparameters associated with each beam set. In this manner, mobilityparameters may be specific to a beam set, thereby enabling moreefficient event detection and beam/cell mobility decisions.

The mobility parameters may include one or more beam IDs of beamsincluded in a beam set. The beam IDs may indicate one or more referencebeams to be measured in an effort to detect an event trigger (mobilityevent trigger). Mobility parameters may include filtering coefficients aUE may apply to measurements of beams within the beam set and/or howheavily the UE should filter the measurements over time. The mobilityparameters may include event triggers, which will be described in moredetail below. One or more event triggers may be based on a relativesignal quality change within a beam set. Additionally or alternatively,one or more event triggers may be based on an absolute signal qualitychange within a beam set. The mobility parameters may include areporting configuration, indicating to the UE when, how, and whatinformation to report to the BS upon detecting an event trigger. Inresponse to receiving an indication of a detected event trigger, the BSmay handover the UE to a target BS or may switch from using a firstactive beam to a second active beam to serve the UE.

A BS may define one or many beam sets for a UE. Each beam set mayinclude a collection of beams having similar functionality orcharacteristic. Accordingly, one or more mobility parameters specific toa beam set may be used to determine a trigger event based on thereference beams in the beam set.

The beam sets may be indicated in a synchronization subframe, such as,for example, in a primary synchronization signal (PSS)/secondarysynchronization signal (SSS)/reference signal (RS). According to anexample, one beam set may include a set of beams transmitted in asynchronization region.

According to an example, one or more beam sets may include beamstransmitted in a non-synchronization subframe. For example, one or morebeam sets may include beams transmitted in a control region and/or adata region. Such a beam set may be based on a collection of referencesignals such as, for example, a measurement reference signal (MRS),channel state information reference signal (CSI-RS), and/or other RS.

Each of the beam sets may have one or more references beams. Thereference beams for the beam sets may be based on beam ID indicated insync subframe (e.g., PSS/SSS/RS) or indicated in the non-synchronizationregion (e.g., control and/or data). Using the received mobilityparameters associated with a specific beam set, the UE may measure oneor more reference beams in the beam set in an effort to detect an eventtrigger.

According to aspects, the reference beam may be selected on-demand andmay be based on an RS, such as a MRS or NR-SS. For example, a serving BSmay transmit, to a UE, a request for a measurement and then may transmitthe RS. The UE may measure the RS and may transmit a report indicatingthe signal strength of the RS to the serving BS. The serving BS mayselect and configure the UE with one or more reference beams based onthe received report.

The signaling between BS and the UE regarding the beams included in thebeam set (e.g., reference beams included in the beam set) and themobility parameters associated with a respective beam set may betransmitted via Layer 1/Layer 2 control channels, Layer 3 signaling, ora combination thereof.

As mentioned above, the BS may configure beam sets based on beamfunctionalities. Beam sets may include one or more reference beamshaving similar characteristics. According, the mobility parametersassociated with the beam set may be set based on the reference beamsincluded the beam set. In this manner, efficient and accurate mobilitydecisions may be made by the BS.

A UE may be configured with one or more beam sets. One or more of thebeam sets may be based on the direction of a reference beam. Forexample, Beam Set 1 may correspond to beam direction 1 and Beam Set 2may correspond to beam direction 2, where beam direction 1 and beamdirection 2 are different. Thus, the beams associated with Beam Set 1may share have a similar direction between the BS and the UE and thebeams associated with Beam Set 2 may have a similar direction betweenthe BS and the UE.

One or more beam sets may be based on the BS associated with thereference beams of the beam set. One beam set may correspond to beamsfrom a first BS and another beam set may correspond to beams from asecond BS. According to another example, a first beam set may includebeams associated with the first BS and another beam set may includebeams associated with one or more other BSs. Stated otherwise, a beamset may include beams associated with multiple cells/BSs.

One or more beam sets may be based on the information being transmittedby the reference beam. For example, one beam set may include data beamsfrom a BS and another beam set may include control beams from the sameor a different BS. As illustrated in FIG. 8, control beams may bebroader than data beams. Accordingly, mobility parameters for controlbeams may be different than mobility parameters for data beams.

The above paragraphs provide examples of beam sets that may beconfigured by a BS for a UE to monitor. In general, the BS may defineone or more beam sets, wherein each beam set includes at least onereference beam. According to aspects, the BS may configure only one beamset.

Mobility parameters may be associated with the beam sets. Each beam setmay have different mobility parameters. According to aspects, based onthe beam functionalities or characteristics, one or more beam sets mayshare mobility parameters.

The mobility parameters may include information a UE may use to detect amobility event. The mobility parameters may include identificationassociated with one or more reference beams for each of the beam sets.Accordingly, the UE may know which beams to measure in an effort todetect mobility events. The mobility parameters may include thefiltering coefficients to use while processing the measurementsassociated with the reference beams of the beam set. The mobilityparameters may indicate events associated with the beam sets thattrigger an event trigger. The mobility parameters may indicate one ormore thresholds associated with the beam sets. A UE may compare signalquality measurements of one or more reference beams in the beam set withan associated threshold value to determine the presence of a mobilityevent. The mobility parameters may indicate a time to trigger (TTT),wherein an event trigger may be detected when the event triggerrequirement is fulfilled in a given time interval. The mobilityparameters may indicate a reporting configuration, indicating whatinformation to report to the BS when a mobility event is detected by theUE.

As described above, the event trigger may be based on a relative changein signal strength of reference beams within a beam set. For example,the UE may have received an indication of N beam sets. Within one of theN beam sets, the UE may determine a signal strength of a reference beamof the beam set is less than a signal strength of another beam in thesame beam set. If so, the UE may transmit an indication of a detectedmobility event. In response, the BS may perform beam or cell mobility.For example, the UE may be handed over to a target BS or the BS mayswitch the active beam used to serve the UE.

According to an example, the mobility parameters may indicate beams IDsassociated with multiple reference beams in a same beam set. Themobility parameter may indicate a threshold value for detecting amobility event. The threshold value may be a difference in signalstrength associated with the two reference beams in the beam set. Thus,when the difference in signal strength exceeds the threshold value, theUE has detected a mobility event.

According to an example, the mobility parameters may indicate a beam IDof one or more selected reference beams in a same beam set. A mobilityevent may be detected when a signal strength associated with anotherbeam (not a reference beam) exceeds the signal strength associated withthe one or more selected reference beams.

According to another example, the UE may measure reference beams in BeamSet 1 and reference beams in Beam Set 2. An event trigger may bedetected when a relative change in signal strength between the measuredbeams in Beam Set 1 exceeds a threshold and/or Beam Set 2 exceeds thesame or a different threshold value. As described above, the UE maytransmit an indication of the detected mobility event. In response, theBS may perform beam or cell mobility for the UE.

The event trigger may be based on an absolute change in signal strengthwithin a beam set. For example, the UE may measure reference beams inBeam Set 1 and reference beams in Beam Set 2. The UE may receive athreshold value associated with Beam Set 1 and Beam Set 2. A signalquality change with respect to a threshold configured for a respectivebeam set may trigger an event. For example, an event trigger may bedetected based on a change (e.g., delta) in signal strength for one ofthe reference beams of Beam Set 1 exceeding threshold value associatedwith Beam Set 1. Similarly, an event trigger may be detected based on achange (e.g., delta) in signal strength for one of the reference beamsof Beam Set 2 exceeding a threshold value associated with Beam Set 2.This is one example of the mobility event trigger being based on achange in signal strength of the reference beam exceeding a thresholdvalue.

According to aspects, beam sets may include reference beams from aserving BS and one or more target (e.g., neighboring) BSs. In this case,the beams associated with different BS may have a similar direction tothe UE. The UE may or may not know which beams are associated with theserving and target BSs. The beam sets may be signaled to the UE by theBS. As described above, the selection of beams for a beam set may bebased on a DL RS transmitted to the UE (e.g., MRS) in a connected mode.

Upon receiving an indication of a detected event trigger, the BS maymake mobility management decisions for the UE. The BS may instruct theUE to switch one or more active beams based on detected trigger eventsassociated with one or more beam sets. According to aspects, the BS mayhand over the UE to a target BS (cell to cell handover) based ondetected trigger events associated with the one or more beam sets.

In scenarios where a BS may communicate with a UE using active beams,the UE and BS may benefit the use of beam sets for beam and cellmobility. Beam sets may include one or more reference beams. Thereference beams of a beam set may have a common functionality. Forexample, the reference beams of a beam set may include only controlbeams, only data beams, only beams from one BS, beams associated with asimilar direction. The beam sets may have associated mobilityparameters. Based on the parameters associated with a beam set, the UEmay perform measurements of reference beams in an effort to detect eventtriggers. A BS may make mobility management decisions based, at least inpart, on a detected event trigger.

As described herein, one set of mobility parameters may not effectivelydetect trigger events for beams having different functionalities andcharacteristics. The use of beam sets and mobility parameters associatedwith a beam set may allow more accurate mobility decisions and savepower at a UE.

The methods disclosed herein comprise one or more steps or actions forachieving the described method. The method steps and/or actions may beinterchanged with one another without departing from the scope of theclaims. In other words, unless a specific order of steps or actions isspecified, the order and/or use of specific steps and/or actions may bemodified without departing from the scope of the claims.

As used herein, a phrase referring to “at least one of” a list of itemsrefers to any combination of those items, including single members. Asan example, “at least one of: a, b, or c” is intended to cover a, b, c,a-b, a-c, b-c, and a-b-c, as well as any combination with multiples ofthe same element (e.g., a-a, a-a-a, a-a-b, a-a-c, a-b-b, a-c-c, b-b,b-b-b, b-b-c, c-c, and c-c-c or any other ordering of a, b, and c).

As used herein, the term “determining” encompasses a wide variety ofactions. For example, “determining” may include calculating, computing,processing, deriving, investigating, looking up (e.g., looking up in atable, a database or another data structure), ascertaining and the like.Also, “determining” may include receiving (e.g., receiving information),accessing (e.g., accessing data in a memory) and the like. Also,“determining” may include resolving, selecting, choosing, establishingand the like.

The previous description is provided to enable any person skilled in theart to practice the various aspects described herein. Variousmodifications to these aspects will be readily apparent to those skilledin the art, and the generic principles defined herein may be applied toother aspects. Thus, the claims are not intended to be limited to theaspects shown herein, but is to be accorded the full scope consistentwith the language of the claims, wherein reference to an element in thesingular is not intended to mean “one and only one” unless specificallyso stated, but rather “one or more.” Unless specifically statedotherwise, the term “some” refers to one or more. All structural andfunctional equivalents to the elements of the various aspects describedthroughout this disclosure that are known or later come to be known tothose of ordinary skill in the art are expressly incorporated herein byreference and are intended to be encompassed by the claims. Moreover,nothing disclosed herein is intended to be dedicated to the publicregardless of whether such disclosure is explicitly recited in theclaims. No claim element is to be construed under the provisions of 35U.S.C. § 112, sixth paragraph, unless the element is expressly recitedusing the phrase “means for” or, in the case of a method claim, theelement is recited using the phrase “step for.”

The various operations of methods described above may be performed byany suitable means capable of performing the corresponding functions.The means may include various hardware and/or software component(s)and/or module(s), including, but not limited to a circuit, anapplication specific integrated circuit (ASIC), or processor. Generally,where there are operations illustrated in figures, those operations mayhave corresponding counterpart means-plus-function components withsimilar numbering. As an example, one or more of the components of theBS 110 and the UE 120 illustrated in FIG. 4 may be configured to performmeans corresponding to the (method) steps described herein. For example,the antenna 434, mod/demod 432, any combination of the processors 420,430, and 438, the and controller/processor 440 may be configured toperform means for transmitting, means for receiving, means for takingone or more actions, means for selecting, and means for performing ahandover. As another example, the antenna 452, mod/demod 454, anycombination of the processors 458, 464, 466, and thecontroller/processor 480 may be configured to perform means forreceiving, means for detecting, means for taking one or more actions,means for transmitting, and means for performing a handover.

The various illustrative logical blocks, modules and circuits describedin connection with the present disclosure may be implemented orperformed with a general purpose processor, a digital signal processor(DSP), an application specific integrated circuit (ASIC), a fieldprogrammable gate array (FPGA) or other programmable logic device (PLD),discrete gate or transistor logic, discrete hardware components, or anycombination thereof designed to perform the functions described herein.A general-purpose processor may be a microprocessor, but in thealternative, the processor may be any commercially available processor,controller, microcontroller, or state machine. A processor may also beimplemented as a combination of computing devices, e.g., a combinationof a DSP and a microprocessor, a plurality of microprocessors, one ormore microprocessors in conjunction with a DSP core, or any other suchconfiguration.

If implemented in hardware, an example hardware configuration maycomprise a processing system in a wireless node. The processing systemmay be implemented with a bus architecture. The bus may include anynumber of interconnecting buses and bridges depending on the specificapplication of the processing system and the overall design constraints.The bus may link together various circuits including a processor,machine-readable media, and a bus interface. The bus interface may beused to connect a network adapter, among other things, to the processingsystem via the bus. The network adapter may be used to implement thesignal processing functions of the PHY layer. In the case of a userterminal 120 (see FIG. 1), a user interface (e.g., keypad, display,mouse, joystick, etc.) may also be connected to the bus. The bus mayalso link various other circuits such as timing sources, peripherals,voltage regulators, power management circuits, and the like, which arewell known in the art, and therefore, will not be described any further.The processor may be implemented with one or more general-purpose and/orspecial-purpose processors. Examples include microprocessors,microcontrollers, DSP processors, and other circuitry that can executesoftware. Those skilled in the art will recognize how best to implementthe described functionality for the processing system depending on theparticular application and the overall design constraints imposed on theoverall system.

If implemented in software, the functions may be stored or transmittedover as one or more instructions or code on a computer readable medium.Software shall be construed broadly to mean instructions, data, or anycombination thereof, whether referred to as software, firmware,middleware, microcode, hardware description language, or otherwise.Computer-readable media include both computer storage media andcommunication media including any medium that facilitates transfer of acomputer program from one place to another. The processor may beresponsible for managing the bus and general processing, including theexecution of software modules stored on the machine-readable storagemedia. A computer-readable storage medium may be coupled to a processorsuch that the processor can read information from, and write informationto, the storage medium. In the alternative, the storage medium may beintegral to the processor. By way of example, the machine-readable mediamay include a transmission line, a carrier wave modulated by data,and/or a computer readable storage medium with instructions storedthereon separate from the wireless node, all of which may be accessed bythe processor through the bus interface. Alternatively, or in addition,the machine-readable media, or any portion thereof, may be integratedinto the processor, such as the case may be with cache and/or generalregister files. Examples of machine-readable storage media may include,by way of example, RAM (Random Access Memory), flash memory, ROM (ReadOnly Memory), PROM (Programmable Read-Only Memory), EPROM (ErasableProgrammable Read-Only Memory), EEPROM (Electrically ErasableProgrammable Read-Only Memory), registers, magnetic disks, opticaldisks, hard drives, or any other suitable storage medium, or anycombination thereof. The machine-readable media may be embodied in acomputer-program product.

A software module may comprise a single instruction, or manyinstructions, and may be distributed over several different codesegments, among different programs, and across multiple storage media.The computer-readable media may comprise a number of software modules.The software modules include instructions that, when executed by anapparatus such as a processor, cause the processing system to performvarious functions. The software modules may include a transmissionmodule and a receiving module. Each software module may reside in asingle storage device or be distributed across multiple storage devices.By way of example, a software module may be loaded into RAM from a harddrive when a triggering event occurs. During execution of the softwaremodule, the processor may load some of the instructions into cache toincrease access speed. One or more cache lines may then be loaded into ageneral register file for execution by the processor. When referring tothe functionality of a software module below, it will be understood thatsuch functionality is implemented by the processor when executinginstructions from that software module.

Also, any connection is properly termed a computer-readable medium. Forexample, if the software is transmitted from a website, server, or otherremote source using a coaxial cable, fiber optic cable, twisted pair,digital subscriber line (DSL), or wireless technologies such as infrared(IR), radio, and microwave, then the coaxial cable, fiber optic cable,twisted pair, DSL, or wireless technologies such as infrared, radio, andmicrowave are included in the definition of medium. Disk and disc, asused herein, include compact disc (CD), laser disc, optical disc,digital versatile disc (DVD), floppy disk, and Blu-ray® disc where disksusually reproduce data magnetically, while discs reproduce dataoptically with lasers. Thus, in some aspects computer-readable media maycomprise non-transitory computer-readable media (e.g., tangible media).In addition, for other aspects computer-readable media may comprisetransitory computer-readable media (e.g., a signal). Combinations of theabove should also be included within the scope of computer-readablemedia.

Thus, certain aspects may comprise a computer program product forperforming the operations presented herein. For example, such a computerprogram product may comprise a computer-readable medium havinginstructions stored (and/or encoded) thereon, the instructions beingexecutable by one or more processors to perform the operations describedherein. For example, instructions for perform the operations describedherein and illustrated in FIGS. 9-10.

Further, it should be appreciated that modules and/or other appropriatemeans for performing the methods and techniques described herein can bedownloaded and/or otherwise obtained by a user terminal and/or basestation as applicable. For example, such a device can be coupled to aserver to facilitate the transfer of means for performing the methodsdescribed herein. Alternatively, various methods described herein can beprovided via storage means (e.g., RAM, ROM, a physical storage mediumsuch as a compact disc (CD) or floppy disk, etc.), such that a userterminal and/or base station can obtain the various methods uponcoupling or providing the storage means to the device. Moreover, anyother suitable technique for providing the methods and techniquesdescribed herein to a device can be utilized.

It is to be understood that the claims are not limited to the preciseconfiguration and components illustrated above. Various modifications,changes and variations may be made in the arrangement, operation anddetails of the methods and apparatus described above without departingfrom the scope of the claims.

What is claimed is:
 1. A method for wireless communication by a basestation (BS), comprising: transmitting, to a user equipment (UE) servedby the BS, information regarding one or more beam sets, wherein each ofthe beam sets comprise one or more reference beams used to transmit areference signal; transmitting, to the UE, one or more mobilityparameters, wherein the mobility parameters are associated with thereference beams and one or more mobility event triggers; receiving, fromthe UE, an indication of a detected mobility event, the mobility eventdetected based, at least in part, on the mobility parameters; and takingone or more actions based, at least in part, on the indication.
 2. Themethod of claim 1, wherein the reference beams associated with at leastone of the beam sets comprise beams having a similar direction betweenthe BS and the UE.
 3. The method of claim 1, wherein the one or morereference beams of a first beam set comprises beams associated with theBS and the one or more reference beams of a second beam set comprisesbeams associated with a target BS.
 4. The method of claim 1, wherein thereference beams of least one of the beam sets comprise beams associatedwith at least one of data beams from the BS or control beams from theBS.
 5. The method of claim 1, wherein the mobility parameters associatedwith the reference beams comprise information regarding at least one of:filtering parameters associated with one of the beam sets, configurationinformation for one or more event triggers, a threshold value associatedwith one or more event triggers, or a configuration information forreporting a detected event trigger.
 6. The method of claim 1, whereinthe mobility parameters indicate beam identifications (IDs) associatedwith two of the reference beams in one of the beam sets and a thresholdvalue for detecting a mobility event trigger associated with the beamset, and wherein the mobility event trigger is based, at least in part,on a difference in signal strength associated with the two referencebeams exceeding the threshold value.
 7. The method of claim 1, whereinthe mobility parameters indicate a beam identification (ID) associatedwith a selected reference beam in one of the beam sets, and wherein themobility event trigger is based, at least in part, on a signal strengthassociated with another beam in the beam set exceeding a signal strengthassociated with the selected reference beam.
 8. The method of claim 1,wherein the mobility parameters indicate a beam identification (ID)associated with at least one of the reference beams in one of the beamsets and a threshold value for detecting an event trigger associatedwith the beam set, and wherein the mobility event trigger is based, atleast in part, on a change in signal strength for a reference beamassociated with the beam ID exceeding threshold value.
 9. The method ofclaim 1, wherein the one or more reference beams of one of the beam setcomprises beams transmitted in a synchronization subframe.
 10. Themethod of claim 1, wherein the one or more reference beams of one of thebeam set comprise beams transmitted in a non-synchronization subframe.11. The method of claim 1, further comprising: transmitting a referencesignal (RS); receiving, from the UE, a measurement report associatedwith the RS, and selecting the one or more reference beams in the beamset based, at least in part, on the measurement report, whereintransmitting the information regarding the one or more beam setscomprises: transmitting, to the UE, an indication of the selectedreference beams.
 12. The method of claim 1, wherein the transmitting theinformation regarding the one or more beam sets comprises: transmittingthe information regarding via at least one of a Layer 1 control channel,Layer 2 control channel, or Layer 3 signaling.
 13. The method of claim1, wherein taking the one or more actions comprises: performing one of ahandover of the UE from the BS to a target BS or switching from a firstactive beam associated with a first beam set to a second active beamassociated with the first beam set for serving the UE.
 14. A method forwireless communication by a user equipment (UE), comprising: receiving,from a base station (BS) serving the UE, information regarding one ormore beam sets, wherein each of the beam sets comprise one or morereference beams used to transmit a reference signal; receiving, from theBS, one or more mobility parameters, wherein the mobility parameters areassociated with the reference beams and one or more mobility eventtriggers; detecting a mobility event based, at least in part, on themobility parameters; and taking one or more actions based, at least inpart, on the detected mobility event.
 15. The method of claim 14,wherein the reference beams associated with at least one of the beamsets comprise beams having a similar direction between the BS and theUE.
 16. The method of claim 14, wherein the one or more reference beamsof a first beam set comprises one or more beams associated with the BSand the one or more reference beams of a second beam set comprise beamsassociated with a target BS.
 17. The method of claim 14, wherein thereference beams of least one of the beam sets comprise beams associatedwith at least one of data beams from the BS or control beams from theBS.
 18. The method of claim 14, wherein the mobility parametersassociated with the reference beams comprise information regarding atleast one of: filtering parameters associated with one of the beam sets,configuration information for one or more event triggers, a thresholdvalue associated with one or more event triggers, or a configurationinformation for reporting a detected event trigger.
 19. The method ofclaim 14, wherein the mobility parameters indicate beam identifications(IDs) associated with two of the reference beams in one of the beam setsand a threshold value for detecting an event trigger associated with thebeam set, and wherein detecting the mobility event comprises determininga difference in signal strength associated with the two reference beamsexceeds the threshold value.
 20. The method of claim 14, wherein themobility parameters indicate a beam identification (ID) associated witha selected reference beam in one of the beam sets, and wherein detectingthe mobility event comprises determining a signal strength associatedwith another beam in the beam set exceeds a signal strength associatedwith the selected reference beam.
 21. The method of claim 14, whereinthe mobility parameters indicate a beam identification (ID) associatedwith at least one of the reference beams in one of the beam sets and athreshold value for detecting an event trigger associated with the beamset, and wherein detecting the mobility event comprises determining achange in signal strength for a reference beam associated with the beamID exceeds the threshold value.
 22. The method of claim 14, wherein theone or more reference beams of one of the beam set comprises beamsreceived in a synchronization subframe.
 23. The method of claim 14,wherein the one or more reference beams of one of the beam set comprisebeams received in a non-synchronization subframe.
 24. The method ofclaim 14, further comprising: receiving a reference signal (RS) from theBS; and transmitting a measurement report associated with the RS,wherein the one or more reference beams in the beam set are based, atleast in part, on the measurement report.
 25. The method of claim 14,wherein receiving the information comprises: receiving the informationregarding via at least one of a Layer 1 control channel, Layer 2 controlchannel, or Layer 3 signaling.
 26. The method of claim 14, whereintaking the one or more actions comprises: transmitting, via a report tothe serving BS, an indication of the detected mobility event; andperforming one of a handover from the serving BS to a target BS orswitching from a first active beam associated with a first beam set to asecond active beam associated with the first beam set.
 27. An apparatusfor wireless communication by a base station (BS), comprising: at leastone processor configured to: transmit, to a user equipment (UE) servedby the BS, information regarding one or more beam sets, wherein each ofthe beam sets comprise one or more reference beams used to transmit areference signal; transmit, to the UE, one or more mobility parameters,wherein the mobility parameters are associated with the reference beamsand one or more mobility event triggers; receive, from the UE, anindication of a detected mobility event, the mobility event detectedbased, at least in part, on the mobility parameters; and take one ormore actions based, at least in part, on the indication; and a memorycoupled to the at least one processor.
 28. The apparatus of claim 27,wherein the at least one processor is configured to: transmit areference signal (RS); receive, from the UE, a measurement reportassociated with the RS, and select the one or more reference beams inthe beam set based, at least in part, on the measurement report, whereinthe at least one processor is configured to transmit the informationregarding the one or more beam sets by transmitting, to the UE, anindication of the selected reference beams.
 29. An apparatus forwireless communication by a user equipment (UE), comprising: at leastone processor configured to: receive, from a base station (BS) servingthe UE, information regarding one or more beam sets, wherein each of thebeam sets comprise one or more reference beams used to transmit areference signal; receive, from the BS, one or more mobility parameters,wherein the mobility parameters are associated with the reference beamsand one or more mobility event triggers; detect a mobility event based,at least in part, on the mobility parameters; and take one or moreactions based, at least in part, on the detected mobility event; and amemory coupled to the at least one processor.
 30. The apparatus of claim29, wherein the at least one processor is configured to: receive areference signal (RS) from the BS; and transmit a measurement reportassociated with the RS, wherein the one or more reference beams in thebeam set are based, at least in part, on the measurement report.